The present invention relates to a cutting device for agricultural machines with several knife bar sections, which are driven so that they are at least temporarily movable in opposite directions and which extend over the working width of the cutting device, the knife blades of which, at the time of a stroke movement of the knife bar sections, interact in a scissor-like manner with counter knives attached fixedly to the cutting device.
A cutting device of the aforementioned kind is known from DE 195 24 039 A1. These cutting devices can be used in particular with cutting assemblies for combine harvesters, but also in mowers for grass or for harvesting other agricultural stalk material.
In DE 195 24 039 A1, it is disclosed to subdivide a cutting device into at least two cutting device portions in order to prevent vibrations and to avoid losses due to shaking. As a result of a phase shift of the driving frequency by 180°, the vibration generated by one cutting device portion is supposed to be compensated by the other cutting device portion and, at best, eliminated. This results in the cutting device portions moving in opposite directions transversely to the working direction of the cutting device. In the case of a movement in opposite directions of the cutting device portions relative to one another, where said portions move apart from one another, a gap forms between them, which becomes larger in the course of the movement and which gradually closes only after the two external dead centers have been reached in the subsequent backward movement and which is closed only for a short time when the two cutting device portions have reached their internal dead center. In the case of a phase shift by a value other than 180° the gap is closed only for a brief amount of time, alternatingly asymmetrically on the right and on the left. In the case of forward travel with the cutting device into an upright crop stand, an unmown strip forms in the area of the gap and constitutes an undesirable crop loss.
The object of the present invention is to keep the width of the unmown strip as small as possible or to prevent it entirely.